河南省崤山金多金属矿集区控矿构造分析与思考

The Metamorphic Core Complex in the Xiaoshan Gold-Polymetallic Concentrating Area of Henan Province and Its Implications for Mineral Exploration

崤山金多金属矿集区位于河南三门峡市境内,是一个典型的变质核杂岩发育区,也是豫西盆岭区的重要组成部分。该区具有优越的成矿地质条件,金-多金属元素异常广泛分布,虽然近年来发现了一些中-小型金多金属矿床和多处矿点、矿化点,但至今没有获得重大找矿突破。本文通过对区域成矿地质条件和控矿要素分析后认为,虽然崤山矿集区与相邻且金多金属矿丰富的小秦岭和熊耳山具有十分相似的成矿背景与地质演化,但本区大型同构造深成侵入体仍处于隐伏状态,表明崤山地体的构造剥蚀与去顶程度远小于小秦岭和熊耳山,这意味着深部应具有巨大的金多金属找矿潜力。因此,要实现崤山地区重大找矿突破,须重视:(1)加大勘查深度;(2)采用行之有效的地球物理探测手段与技术组合,对控矿断裂的深部结构进行高精度探测;(3)加强矿田构造与矿化垂向分带研究,重视与邻区(小秦岭和熊耳山)成矿系统的地质对比与参照。建议对本区有利找矿区段进行高精度地球物理扫面,配合典型断面的地质-地球物理交叉验证,进而优选出可供工程验证的深部找矿靶区。

Located in Sanmenxia city, Henan Province, the Xiaoshan gold-polymetallic concentrating area is underlain by a typical metamorphic core complex （MCC）, and an important part of basins and ranges of western Henan. Good geological conditions of mineralization is present this region, where geochemical anomalies of Au and related elements are widely distributed in mineralized altered-rocks and auriferous quartz veins, both are hosted within shear zones or fractures of varying sizes and orientations. Several small- to medium-sized gold-polymetallic ore deposits, as well as numerous clustered occurrences, have been found in recent years. Although the Xiaoshan district has traditionally been deemed as an excellent geological endowment area with great potential in finding large-sized deposits, no significant discovery is made to date. Based on our comprehensive studies on regional metallogenic setting and ore-governing factors, it is considered that the Xiaoshan terrane should have a comparable resource potential to the adjacent Xiaoqinling and Xiong’ershan, both host tremendous gold-polymetallic deposits, since they have identical or similar metallogenic settings and geologic evolution. Nevertheless, there are sufficient geological evidence indicating that the exhumation and tectonic un-roofing of the Xiaoshan MCC terrane was much less than those of Xiaoqinling and Xiong’ershan terranes, implying mineral potential beneath the Xiaoshan region existing at considerable depths, which consequently hinters prospecting efforts. In order to realize ore-finding breakthrough in this area, the following geological and geophysical approaches are suggested： 1） increasing exploration depths for more than 1500 m from surface in the region; 2） adopting the most effective, appropriate deeply-penetrating geophysical methodologies with high precision and their combinations to figure out favorable targets with potential gold-polymetallic mineralization; and 3） carrying out detailed studies on ore-controlling structures and regional metallogeny to better understand the mineralizing processes, hydrothermal fluid pathways and ore localizations. By applying geophysical grid surveys over carefully-selected prospective areas combined with appropriate geologic-geophysical profiling for cross-testing and correlation, the sizes, orientations and spatial distributions of the ore-hosting ductile-brittle shear zones can be effectively delineated, and finally the preferential targets under cover will be sorted out for further drill-tests and ensued geological exploration.